Rotary engine.



T. J. BI'GGS.

ROTARY ENGINE.

APPLXGATION HLBD JANJ, 1914.

15,1 1 1,053, Patented Sept. 22, 1914.

....rfy/f @woe/mbo@ T. (Y. BMGS.

ROTARY ENGINE.

.APPLIGATION MLBD' JANQ?, 1914.

Eatenled Sept. 22, 9141.

5 SHEETS-SHEET 2. 5H

T. J. BIGGS.

ROTARY ENGINE. APPLIGATION FILED JAN.7,1914.

` Patented Sept. 22, 19147.,

T., J. BIGGS.

ROTARY BNGlNE.

APPLICATION FILED JANJ, 19m

EL? :i l SS y Patented Sept, 22, will.

www f /L x .Tu LBIGGS.

ROTARY ENGINE. APPLIGATIN NLED JAN.7,1914.

, 1,111,053, )Patented sept. 22, 1914,

22 5 SHEETS-SHEET 5.

l. A.. J. Makati... 0

nofran'r itineranti.

Lili lhth'i.

Specification. o Letters latcnt.

Patented nep-t. 25%, wird..

applicativa ined January 7, wie. serial no. einen.

To all 'wilma it may concern f lle it known that l, Tnonas J. Brees, citizen of the lUnited States, residing at @ak (lreel, county of lioutt and State of Colorado, hare inrented certain new and use'tul Improvements in' Rotary Engines; and l do declare the following; to be a full, clear, andA exact description of lthe invention, such as will enable others skilled in the art to which it apperl'ains to make. and use the same. rei crcnf-e being had to the accompanying draW- infie, and to the letters and figures of refereure marked thereon, which form a part of this speciication. y

I ."ily invention relates to improvements in rotary engines adapted-to be operated by steam. air, or other similar gras, 'my object beine' to provide a construction oit' this cliaractor which shall be exceedingly eilicient for the purpose intended.

An important object or" .my improved construction consists in the 'Fact that provision is made 'for cutting ott the inlet of the steam, or other Huid. at predetermined points durinn the travel oi' the rotor, whereby the completion of the rotary movement ot" the latter is accomplished on expansion. It is evident that this construction may be operated by air, or other similar glas, as Well as steam. though in this specification it will be assumed that the fluid employed `is steam. Provision is also made for cutting oii1 the exhaust. as the sprii1 .e-actuated blade carried by the rotor' approaches the con1pletion of its revolution, the rotor for this purpose being; made eccentric by enlarge` ment on theside where the blade is located.

The rotor is eccentrically mounted in a casing' whose Wall is providedwitli a passage in communication with ports leading trom the main chamber ot thecasing. said ports beingg` controlled by manually operated ralres. This passage connnunieates with a plunger. whereby the steam as it enters the passage troni the main chamber of the casin e; operates` the plunger and cuts otl the supply of lire steam to the main chamber, alter which the rotor completes its stroke or revolution on expansion.

is illustrated in the drawing. three ports are employed, arranged at suitable inten 'vals around the main chamber. Any one of these portsmay be opened by the proper nianipulation oi2 its valve, to cause 'the live fluid to besluit from the main chamber -in which slightly more than hall a revolution, as'

when the operating; blade has passed any one of the ports.

chamber during* the entire revolution of the rotor. However, after the rotor has reached its normal speed, one of the'valves may be opened for permitting1 the escape oi" the steam into the aforesaid passage as soon as the actuating; blade has passed the desired exit port.

Having briefly outlined my improved construction, l will proceed to describe 'the same in detail, reference being made to the ac compaiiying' drawing, in which is illustrated an embodiment thereof.

.lfnthis dra-Wing: Figure 1 is a cross-section cutting the rotor of my improved ro* ntary engine. Fig. 2 is a longitudinal section of the same, or a section cutting theA axis of the rotor longitudinally. Fig. 3 is fragmentary section similar to Fig. l, but showing' the rotor in a difierent relative position. Fig. t is still another View illustratinnr the. rotor in still another position. Fig. 5 is a vie\v similar to Fig. l, but showine the rotor in a dilerent position, namely, its` actuating blade .has made compared `with the position shown in l. Float is a section similar to Fig'. 5, but showing a modified form of construction. Figs. i' and 8 are detail views illustrating; the manner of actuating' a valve employed in connection with the construction shown in Fig. (i.

Referring iirst more especially7 to Figs. l to 5, inclusive, let the nume-ral 5 designatea main casing, which as' illustrated in the drawing' is centrally divided by a partition G forming the inclosed chamber int/o two approximately equal compartments 7. ln each .of these compartments is eccentrically mounted a rotary member 8, which is se? curedto a shaft 9 being splined thereon,

l2, which is freely slidable in a chamberf..

E formed in the rotor and in which is lo.-

cated a spiral spring; le, which acts upon the blade to :torce the latter: outwardly into the chamber 7. Thei'projectng part ofthe blade is acted upon by 'thesteam trom the l 16, formed in tlietop member 17 of the valve 'crank-2 1 is applied for manually manipulat-l chest. This valve 15 is journaled'as shown at 18 in the end walls 18 of the steam chest, these walls being secured to the body of the chest by means of bolts 20, or other suitable fastening devices.

To one extremityof the valve 15,` w'hich extends beyond the valve chest, a handing the valve This Valve controls'the inlet and Qexhagust ofthe steam from the main chamber inwhich the rotor operates. In m improvedconstruction the .rotors may, o! course, :travel in eitherV direction. When itisfdesiredto change the direction of travel of the rotors, thevalve 15 is shifted accordingly, whereby the passages through Which'the live steam originally passed to the main chamber, become the passages through4 which the exhaust escapes therefromfandvicel'ersav .l that the valve 15 is in the posi tion bestfil ustrated in Fig. 1thelive steamV whichenters the steam chest through a nip-- ple 22,'passes throughthe'valve 15, as shown at 23,"and enters the inlet side`24 .of 'the steam chest', whence. it 'travels through a portf25 and a passa e 26 formed in a slide vvalve 27,into the c amber 7 of the main casiri 5. The steam after enterin this chamger acts upon thev portion 'of thegblade 12 which projectsbeyond the rotor, and drives. the latter.

vIn'the drawing it -is assumed that each `ro- .tor is travelin inthe direction indicated by .the arrows.4 he wall of the casing ispro- Avided with a passage 29, which communicates with. the main chamber 7 by means of ports 30, 31 and 32, the said ports being contrailed by spindle valves 33, a4 and a5.

. 'The valve 33 is located a proximately onelfourth the distance aroun the valve cham ber, from the point 36,. which may be a'ssumed is the point where -the operating blade 12 commences its revolution. Now, if it isdesired to permit the live steam to Venter the chamber 7 during ap roximately one-fourth of theI revolution ci) the rotor, only, the` valve 33' may be opened to allow a small portionof the steam to enter the passage 29 through the port 30. This passage y communicates at its upper extremity on each side of the .casing with a` pipe 37, which leads t'o a small chamber 38, in, which is located a plunger 39 secured t o one extremity of a rod 40, whose opposite extremity carries a cut-off valve 41, which when the plunger '23 is actuated fromabove, as the steam enters the chamber 38, is moved to the position shown in Fig- 1, whereby the travel of livesteam through the port-25 is cut oi. Hence during the balance of the rotary stroke of the rotor the latter must be In this event the live steam is cut oil' ,after therotor has completed'approximately one` half of its stroke and the balance of its stroke or revolution is completed on'expansion. However, if it should be desired to cause the rotor to travel only a quarter, approximately, of itsA revolution byiexpansion, the two'valves 33 and 34 would be leftl closed and the valve 35 opened. This is, of

course, as'suming'that the rotor is traveling in the direction of the arrow in Fig. 1. Of course, if the rotors were travelin order to produce the result stated, would be reversed. Each rotor 'of 'my the side Where the operatingblade 12 islocated. The enlargement or variation lfrom the lcylindrical form, beginning at approximately the points A on opposite sides of the rotor, from which points the latter is radually Venlargedto the center of the b ade. or to the point indicatediby the numeral .3.6 in Fig. 1, By virtue of this enlargement of the rotor, the supply valve 27 isv closed, while the rotor is traveling from the point A to one extremity B of a cavity C formed in the rotor on oppbsite sides of the enlarged portion of the rotor. Thesecavities increase in depth from the point B tothe point l). The wheels` of the rotor, however,-beyona the cavities, actuponhe slide valve 27 tcraise the latter until the blade 12 reaches the said valve, in which went the blade serves to support the valve in the` raised positionagainst its spring. Y.

in the opposite direction the order in w ich the` valves 33, 34 and 35 would be opened, in"

improved construction `1snot a perfect cylinder, but isv enlarged en'd By, inspection of the drawing it will be .Y

seen that the blade 12 extends the full length of the rotor, while the cavities 13 are of'less 'wldth than the rotor, (see dotted lines in Fig.. 2) leaving the walls of the rotor intact on 4opposite sides of the' cavities for slide valve operatin pur oses. The slide va ve 2 not only contains the ports and passages 25 and 26, but also openings 42, in which cutl-oi valves 41 operate.

valves 41, but their 15 in 'that view, lthe ex minces ing and closing movement, a stem a3 isA threaded into the central portion of the valvev as 'shown at 44, and passes through slots d5 formed. in the inner wall 46 oit the steam chest. v f By reference to Fig. l of the drawing it Will be understood that it' the steam enters the chamber 7 on the lett hand side of the slide valve,.due to the osition of the valve iaust will take place on the opposite side, and consequently through a passage 26 and a port 25, which in t-hls event becomes the exhaust port. However, as during the reverse operation ci the rotor, the inlet ports and passages, as illustrated in Fig. `l, would become the exhaust ports and passages, l have chosen to give theports and passages on both sides oit the slide valves corresponding reference characters. The exhaust from either side 2li of the steam chest willv pass from the upper portion of the compartment 24 through a port 47, into a passage 48 of the valve l5, and thence into and through a port ,49 of the valve chest into a passage 50,

whence it escapes to the atmosphere. (See dotted lines in Fig. 2).

From the foregoing description the operation of the construction, as thus tar described, will be readily understood. Assuml ing that the live steam taires the course indicated in Fig. l, by virtue of the position. i of the valve, illustrated in said figure, the e steam Will enter nipple 22 and travel thence through the valve opening' 23 to the lefthafnd compartment 24 of the valve chest, l thence through a port 25 in the slide valve to a passage 26 in the saine valve, and thence l into the chamber 7 ot the main casing, assuming that the slide valve is in position to permit such action. (See Fig. 5) rlhis steam will then act upon the blade 12 and drive the rotor in the direction indicated by i the arrows in Figs. l and 5, or toward the l left. Now, if we assume that the port 31 ot' the valve casing is open by virtue ot' the position of the valve 34'shown in. Figs. l and 5, as soon as the ,blade l2 passes said port the I steam will enter the passage 29 and travel thence through the pipe 37 upon the left hand side or' the valve chestto the chamber l 38 and act upon the plunger 39 through the stem 40 to move the cut-oil valve /ll down Wardly a sufficient distance to close the port i 25 and shut oil the live steam from the passage 26' and consequiently from the chamber Il `7 ot the` main casing. The steam Within the chamber 7 between the slide valve and the blade l2 on the left-hand side, referring to Fig. 5, will act by expansion upon the blade l2 to complete the stroke or revolution of the rotor. As soon as the point located at A, approximately, on the right-hand side of the rotor, still referring to Fig. 5, reaches the 'lower extremity of the slide valve` the l en (l.)

latter will begin to more upwardly and willbe closed by the time the rotor has traveled sufticiently to bring thlesmaller, extremity B of the cavity C beneath the adjacent portion of the slide valve. In this event, the exhaust from the portion oil" the chamber '7 on the right of the blade will be cut oli'. This exhaustz up to the time of its cut-oil', has been escaping' through the passage 26 on the right-hand side of the slide valve, the port 25 on the same side, into the adjacent compartment 24 and thence through the opening 48 of the valve 15, into the opening 4-9 of the valve chest, and thence into the passage 50 and out to the atmosphere through the opening. Assuming, namely, that the escape ot' this exhaust is cut ofi, by virtue oi the fact that the point B ot the rotor occupies a position directly below the nearest portion of the slide Valve, trapped in the cavity C. However, were it not for this cavity the steam would be compressed within the portion of the chamber 7 between the point B of the rotor and the blade l2. However, as soon as the point B of the chamber C passes the lower extremity ot the slide valve, the chamber C in question is brought into communication with the chamber 7 and the pressure on both sides of the blu-:le

will exist until the blade l2 has passed the slide valve, after which the latter begins to open and allows the live steam to cntcr the chamber 'T in the rear ot' the blade and the operation continues. During thc time that the slide valve remains time the pressure on both sides of the blade 12 is balanced, as to one of the rotors, whereby this rotor is virtually inactive and asserts no power upon the shaft 9, the other rotor, whose position is the reverse, is acting to drive the shaft. lt is, therefore, ad vantageous that these rotors should be operated in pairs and reversely arranged, best illus trated in Fig. 2.

the exhaust being l2 is equulized and this condition 1;

closed and during the ln order to insure the balancing oi" the pressure on both sides of the blade during the period heretofore explained, l may enr ploy the construction illustrated in Fig'. G, in which event the blade charnbered, as shown at 52, to the l-l, and the rot-or is provided with a cavity separated into two compartments by a vulve 84, having a passage 55, which is adapted to connect either of two passages 5d formed in the rotor with one compartment These passages -i communicate respectively with the chambers C by' way oi' ports S5 formed in nipples 56, which are threaded into openings in the rotor which register with the enlarged,extremities 57 of the passages 5st. The ports 85 are normallv closed by ball valves vi'hich nre acted on by spiral springsf. New, as the blade i2 approaches -tilsslide valve after the latter has been closed to'shut o' the exhaust, l if there is anyexces'sive pressure in the cavity 13 which is nearer the slide valve, this will act upon the 'corresponding ball valve 58 to open the latter and allow the steam topass into the right-hand compartment y53, (assuming that the rotor is traveling in the direction indicated by the arrows in Figs.

1, 5 and 6) and this pressure within the com! pertinent 53 will act upon a ball valve- 60,

which normally closes the inner extremity 58 will also open the valve 60, assuming that the pressure acting upon the valve 60 in one chamber C is less than that acting u on the valve 58 in the other chamber C.

' l ence, by virtue of this arrangement the pressure may be equalized on both sides of the blade 12, during the period when said blade should bel-inactive. Of course, ,when the rotor is traveling in the opposite direction, the valve 84 must also be reversed, and

' in order to accomplish this, mechanism illusi in Fig. 6 tothe dotted line position in the` trated in Figs. T and 8 may be employed. In these views the numeral G5 designates a sleeve which is normally adjustable upon the shat,-but fixed thereto to turn therewith in either position of adjustment. This sleeve is provided with a lug 66 which is pivotally connected, as shown at 71, with one extremity of a link 67, whose opposite Icxtremity is pivotally connected as shown at 72 with a crank-arm 78 which is made fast, as shown at 73, to one extremity of the valve 84.

The rotor is provided with a rib 68 which is interrupted to form two shoulders G9 and 70. The space between these shoulders indicates'the movement of the sleeve 65 in order to shift the valve 84 from the position shown by full lines in Fig. 6 to the positionshown by dotted lines in the same ligure. orinstance, assuming that whenthe valve 84 is in the full line position in Fig-.6 the parts just described are in the position shown in Fig. 7, if it isdesired to reverse the engine, whereby the rotor is caused'to move in a direction opposite that indicated Kby the arrow in Fig. 6 the throttle valve 15 will be shifted from the full line position same figure, and at the same time the sleeve 65fwill be manually shifted from the position 4shown in 7 to that shwnin Fig. 8, whereby a partial rotarymovernent will be'imparted tothe valve 84' suici'ent to` change the position of thelatter from the position shown in lfull lines in Figf to the dotted line position in the same view.

ln this event, the steam will enter the left- 'coxupartment 53 of the cavity in lthe rotor` and ass out of said cavity by unseat-- ing the lefE-ihand ball valve 60, in order to equalize thepreure 'in the two recesses or relatively shallow cavities C.

The operati'om the form-of construction shown in Fig. 6 will now be connectedly described? Assuming that the rotor is traveling in the direction of the arrow in this view, it will be understood that-'as the blade 12 approaches the slide valve, as soon 'as the point B of the forward cavity, (This term heilig used with reference to the direction of' travel) reaches the slide valve, the vlatterY will be raised suiiciently to close the valve and cut oil' the exhaust from the chamber 7.

Now, while the point B of the forward cav ity C is traveling past the slide valve, there will be slight compression between the blade 12 and the last named valve, as the latter still protrudes slightly into the'chamber 7. This excessive pressure will nd its wayv -into the left-hand compartment53. of the interior cavity in the rotorby unseat-ing the forward valve 58, this excessive pressure being there by stored in the said compartment. As soon as the point B of the foremost cavity C passes the slide valve, the foremost cavity C will be placed in communication with the {luid pressure in the main chamber 7,;Whereby the pressure will be equalized on both sides of the blade 12 and this rotor member will be inactive until the bladev has passed the slide vvalve and until thepoint B ,of the rearmost cavity 13 has 'also passed beyondv the slide valve. As soon as this occurs, the slide valve will begin to open into the chamber 7 and by thetime the forward point A of the rotorhas passed the slide valve the latter will be fully open, as shown' in Fig. 5, for both inlet and exhaust purposes, and the rotor will continue its forward-travel in the direction of the arrowin Eig. 6,' and under the influence of the live steamV until the blade 12 has passed the port 31 of the casing in which event the motive iiuid will enter the passage 29 and pass thencethroughv the lefthand pipe 37 into the chamber 38 where itl will act upon the 1eft-handplunger '39 Y through the stem 40 to actuate the auxiliary valve 41 to close thelport 25' of the slide valve, whereby the inlet of live motive fluid to the chamber 7 and the rear of the bla/de or piston will be cut 0H and the balancef-of the stroke will be completed on expansioni. In

'this last named description I have assumed that the valve 34 is open, so that one-half of the revolution of the rotor is accomplished' on expansion. It is evident, however, that the valve 33 might be opened, whereby ap- Iproxirnately 'three-fourths of the'4 stroke would be accomplished on expansion. Furthermore, if desired, the valve 35 might be `lett open while the valves 33 and 34 .were closed. In this case, approxunately one,- 13o minous i fourth ot the stroke only vvonld'be accompllshed by'expansion ot the motive fluid.

Attention is called to the tact that immediately after the fpoint Bhas reached the slide valve and actuated the same sufficiently to cut otl the exhaust, whereby a slight encessive pressure l.results between the blade andthe inner extremity of the slide valve, causing-the iorernost ball valve 58 to open to relievesuch excessive pressure by causing it to enter the right-hand compartment 53 oi the interior cavity of the rotor, if the pressure Within this compartment is greater than that in the chamber 7, the ball valve 60 will open and relieve the same, producing a balanced result on both sides of the blade, even before the point B of the small cavity 13 has passed the slide valve. llt will then be understood that the pressure on both sides of the slide valve is equalized because the chamber onboth-l sides is continuous and this balanced condition lwill continue until the slide va veis allowed to open, as heretofore explained. f

When it is desired to reverse the engine causing the rotors to travel in the direction oppositethe arrow in Fig. 6, the throttle valve `-l5 will be shifted from the full line position to the dotted line osition in llig.

6, whereby the live steam will enter the cas ing chamber by Way ci? the right-hand compartment 2li of the steam chest, the righthand port 25 and the right-hand passage 26 `of the slide valve. 'lin this event the valve 84 Will be shifted from the full line position to the dotted line position in Fig. 6, and the I operation Will be substantially the same as heretofore described, the only did'erence'be- :ing that what was the foremost cavity C when the rotor Was traveling in the direction of the arrow in Fig. 7 will become the rearmost cavity, While'the rearmost cavity under the conditions originally assumed Will now be the foremost cavity. Having thus described my invention, what l claim is: A

1. ln a rotary engine the combination with a casing of a rotor eccentrically mounted therein and having a crescent shaped enlargement on one side Whose point ot maximum depth reaches the Wall ofthe chamber at the point of minimum separation from the rotor, a blade carried by the rotor and spring-held in engagement with the inner surface of the vvall of the casing, said position ol the' blade being coincident with that ofthe greatest radial depth of the rotor, a valve for controlling the inlet and exhaust of the casing chamber and forced outwardly to the closed position by the enlargement of the rotor.

2. ln a rotary engine the combination with a casing of a r'tor eccentrically mounted. Y therein and having a crescent shaped enlargement on 'one side whose point oi? mani-- erated on expansion duringthe remain mum depth reaches the Wall oi the chamber at the point of minimum separation l'rom the rotor, a blade carried by the rotor and spring-held in engagement with the inner surface oil 'the Wall of the casing, said posi-m tion ci the blade being coincident'with that of the greatest radial depth ci the rotor, and a valve for controlling the inlet and exhaust of the casing chamber and forced outwardly to the closed position by the enlargement of the rotor, the said enlargement having cavi ties ou opposite sides oit the blade to equalize the pressure on both sides of the latter afterI the said valve is closed.

3. ln a rotary engine the combination with a casing of a rotor eccentrically mounted therein and having a crescent shaped en largement on one side which is centrally interrupted by a ,radial recess, la blade located in said recess and Fspringactuated to tangentially engage the inner surface oi the Wall oi the casing at all times, and. a valve spring-actuated to enter the casing lor conv trolling the inlet and enhaust the motive fluid, said valve being actuated by the cresfcent shaped enlargement ol the .rotor for closing purposes before the rotor reaches the position where the outer entrenn'ty` ci its blade is llush with surface.

ll. in arotary engine the combination. With a casing, et a rotor eccentrioully mounted therein and having a crescent shaped eno largement on one side which is centrally interrupted by radial recess, blade located in said recess and springactuated to tangentially' engage the inner surface of the Wall ci thecasing at all times, and a valve springactuated to' enter the casing tor controlling the inlet and exhaust of the motive fluid, said valve being actuated by the crescent shaped enlargement ol the rotor for closing purposes before the rotor reaches the position where the outer extremity ot its blade is flush With its surface, the rotor having cavities in its enlargement on opposite sidesl of the blade to balance the pressure after the closing ci the valve when the rotor is traveling in either direction.'

5. ln -a rotary engine the combination with a casing of a rotor eccentrically mounted therein and having a springnctuatecl blade tangentially engaging the inner surface oi the Walls of the casing a main valve controlled by the rotor, means for controlling the inlet and exhaust oi motive fluid 4from the casing chamber in front and rear oli the blade and means located at suitable intervals around the circumference oil thel casing chamber tor shunting relatively small quantities of motivo valve acted on by said shuntcd liuid to cut oiln the fluid supply to the casing chamber v ia the main waive, whereby the rotor is opof the strolreq i duid, and an auriliary ,I

lll

dit

Mill

lgl li 6. Infa rotary engine the combination of a casing, a rotor eccentrically mounted therein and having a blade tangentially engaging the inner surface" of the casing a main valve controlled by the rotor, the Wall of the casing having a passage, a Huid-inlet.- cut-oftvalve in communication with thesaid passage, and a third valve operable to pery'main valve controlled by the rotor, the Wall of the casing having a passage, a fluid inlet cut-oli valve in communication with the said passage and aplurality of valves arranged at suitableintervals around the circumference of the casing chamber and 0perable to admit small quantities of fluid to the said passage to move the Huid inlet cutolf valve to the closed position.

8. In a rotary engine the combination of a casing, a rotor eccentrically mounted in the casing and having a blade tangentially engaging the inner surface of the casing, the wall of the casing having a passage, a main valve for controlling the motive iluid inlet and exhaust of the casing chamber, said valve being positioned t'o enter the casing nearest the Acenter of the rotor in a radial direction, an auxiliary fluid inlet cut-off valve in communication with the said passage, and a shunt valve operable to permit a relatively small quantity of motive fluid to enter said passage to move the auxiliary cutoff valve to the closed position after the blade of the rotor has passed the shunt valve.

9. In a rotary engine the combination of -a casing, a rotor eccentrically mounted in the casing and having a blade tangentially engaging the inner surface of the casing, the wall of the casing having a passage, a main valvefor controlling the motive fluid, inlet land exhaust of the casing chamber,l said valve being positioned to enter the casing' nearest the center of the rotor in a radial4 direction, the rotor having an--enlarg'elnent on one side to force the said valve outwardly,

the valve being normally spring-actuated toward the casing chamber, an auxiliaryf fluid inlet cut-off valve incomm'unication;

With the said passage, and a pl1 1ralityl of j shunt valves arranged at suitable intervals,

around the circumfrence of the casing .cham-' ber and operable to admit small quantities (son iliary Huid inlet cut-off valve to the closed of fluid to the said passage to move the aux-y interrupted by a recess formed in the rotor, a spring-actuated blade located in said recess and Whoseouter extremity when engaging the yportion of the inner surfacei of the casing nearest the center of the rotor, 'is flush with the outer surface of the enlargement, a i

terior compartment therewith, and outwardly opening check valves respectively controlling ports connecting the exterior cavities with the interior compartments."

.v In testimon whereof I affix my signature 1n presence o ltwo witnesses.

THOMAS J. BIGGS.- Witnesses L. F. HALL, A. EBERT OBRIEN. 

